Japan’s central bank formally adopted a 2 percent inflation target Tuesday and also introduced an open-ended asset purchasing method as part of its aggressive monetary stimulus measures intended to revive the economic growth momentum in the world’s third largest economy. The central bank will purchase 13 trillion yen ($145 billion) in assets every month from January 2014 including 2 trillion yen in Japanese government bonds and about 10 trillion yen in treasury bills.

“The bank will pursue aggressive monetary easing, aiming to achieve the above-mentioned price stability target, through virtually zero interest rate policy and purchases of financial assets, as long as the bank judges it appropriate to continue with each policy measure respectively,” the BoJ said in a statement.

Japanese stocks jumped more than 0.8 percent before falling back into a negative territory as the yen regained ground against the dollar. The yen declined against the green back after the BoJ announcement but picked up later as the new scheme for additional purchases only comes into effect in January 2014.

“The BOJ met expectations by setting a 2 percent inflation target and delivered a surprise by adopting the open-ended pledge to buy assets. One point to note is that asset buying under the open-ended pledge is only set to start from 2014. From 2014 onwards, it's positive... From now until then they are not doing anything more aggressive to weaken the yen,” Roy Teo, FX strategist for ABN AMRO Bank in Singapore, told Reuters.